The present invention relates generally to protective enclosures for fluid flow devices and fluid flow control devices (hereinafter collectively referred to as "fluid flow devices"), and more particularly to protective enclosures having a plurality of insulated modular panels and a hinged roof.
A fluid flow device, such as a valve, pump, or backflow prevention device, typically includes a metering or control mechanism to regulate the fluid flow within, into or out of a piping system. In the case of a backflow prevention device, one or more check valves are incorporated into a fluid flow line to prevent the backflow of any liquid and contaminated matter into the main fluid line. Many of the aforementioned fluid control devices are installed outdoors, either above ground or above the freeze line of the ground. Therefore, in certain geographical areas it is important to enclose such devices to protect them from hostile weather conditions, particularly freezing temperatures.
Fluid flow devices often require maintenance and/or testing to insure that the device is operating properly. Thus, in addition to providing protection from the elements, enclosures for fluid flow devices must also be configured to enable easy access to the fluid flow device contained therein.
There have been several attempts to devise enclosures which protect fluid flow devices from freezing temperatures and which also provide access to the device for testing and maintenance purposes.
One such attempt was disclosed in U.S. Pat. No. 4,890,638, issued to Davenport and incorporated by reference as if fully set forth herein. The Davenport patent discloses a protective enclosure for a backflow prevention device including a rectangular cover member having insulation top and side walls secured to a platform member. One of the side walls is provided with a drain opening adjacent the platform member. The side walls may be sub-divided into removable side panels to facilitate access to the interior space of the cover member. U.S. Pat. No. 4,726,394 and U.S. Pat. No. Reissue 33,523, issued to Devine and incorporated by reference as if fully set forth herein, are both directed to a heated cover for pipeline backflow preventer component assembly. The Devine patents disclose a heated, insulated cover for a portion of a pipeline with valve and backflow preventer components. The cover is sectionalized into several side sections and top wall segments adapted to be joined along longitudinal and transverse lines and clamped together. The cover further includes a drain opening and doors to permit access to the interior of the cover.
A conventional BFP device includes a pair of check valves, a relief valve and shut-off valves positioned in a straight run of pipe. The length flange-to-flange of a traditional BFP for larger diameters is excessive. When elbows are added the flange-to-flange length may increase as much as fifty percent, thus requiring that the enclosure be even longer. These large above-ground assemblies and enclosures are expensive to install and may create undesirable obstructions, particularly when located near a street.
The trend in the manufacture of BFP devices is toward smaller, compact designs. For example, many BFP devices now comprise a vertical or "N-shaped" configuration in which one of the check valve covers is removable from the top of the valve assembly, and the other check valve cover is removable from the side of the valve assembly. The devices disclosed in the above-mentioned patents are designed to accommodate BFP devices having a conventional inline configuration. Accordingly, the enclosures provide removable side access panels or doors to facilitate maintenance of the valve assemblies, but they do not provide any means of access from the top.
One style of enclosure, manufactured by Hot Box, Jacksonville, Fla., and sold under the trade designation Hot Box.RTM., comprises a generally square or rectangular structure having a front wall, a back wall, spaced apart side walls and a hinged roof portion. The roof portion further includes a top, a front and spaced apart triangular sides. Accordingly, the roof may be opened to enable partial front and top access to the BFP device.
Another enclosure, manufactured by Pennsylvania Insert Corporation, Spring City, Pa., and sold under the trade designation Just Set.TM. Thermo Shelters, is similarly configured. The Thermo Shelter comprises two triangularly shaped sections hinged to form a generally square or rectangular structure. The roof portion may be opened to enable front and top access to the BFP device.
The configuration and location of the access means of these enclosures are incompatible with the configuration of many of the compact BFP devices now in use. Neither of these enclosures enables full side access to the valve assembly, which is preferred for the compact BFP configuration described hereinabove.
For example, the walls that comprise the bottom portion of the Hot Box.RTM. enclosure limit a repair person's ability to observe the check valve of the BFP, restrict the repair person's access to the check valve and impair the repair person's ability to easily remove the components of the valve body. Another drawback associated with the Hot Box.RTM. device is that the bottom portion of the enclosure extends above the level of test cocks that are located just above the bottom flange of the BFP, thus preventing full access for testing purposes. Furthermore, the configuration of the Hot Box.RTM. enclosure restricts the degree of rotation of a valve wrench, should one be required to operate the hand wheel of the gate valves of the BFP device.
Another enclosure, manufactured by G&C Enclosures, Inc. and marketed under the trade name Water Safe, comprises a plurality of walls, including access panels, and a top attached to the walls. The top comprises two panels hingedly attached such that one panel may be pivoted open to overlie the adjacent panel. However, this configuration restricts access through the top of the enclosure to one-half of the enclosure area, thus limiting the accessibility of the entire BFP device.
Thus, while enclosures for fluid flow control devices provide some means of access to the device contained therein, the configurations described hereinabove are known to be limited in their usefulness when used with certain valve assemblies. Accordingly, it would be advantageous to invent an insulated cover or enclosure assembly that is configured to accommodate and to enable full access to all of the components of compact BFP devices.